The present invention relates to a method of forming a single-piece polymethyl methacrylate (PMMA) intraocular lens (IOL) having a central lens body and colored positioning loops extending therefrom and to a PMMA core member and lens formed in and by the method.
One-piece IOLs are widely used for implantation in both anterior and posterior chambers of the eye. Such single-piece IOLs are commonly fabricated of PMMA, a polymer which is known for its long term stability and biocompatibility. Currently, all such IOLs are constructed of a clear or colorless transparent PMMA, which may be formulated with a UV-absorber to protect the retina of the eye from ultraviolet radiation present in solar flux.
Clear transparent IOLs, particularly those implanted in the capsular bag or sulcus of the eye are difficult to visualize and manipulate during implantation. For this reason, it is common in the case of IOLs having separate positioning loops staked or otherwise secured to the central lens body of the IOL, for the positioning loops to be formed of a colored material. Examples of such IOLs are the Styles 30, 31 and 34S manufactured by McGahn Medical/3M, the Model G704M Capsulform lens manufactured by IOLAB, and the Model PC-80 lens manufactured by American Medical Optics. The colored positioning loops of such lenses are readily visible and easy to manipulate during implantation. To date, however, commercially available single-piece IOLs, particularly those fabricated of PMMA, have not included colored positioning loops. Hence, such IOLs are difficult to visualize and manipulate during implantation.